This disclosure relates to a gas turbine engine, and more particularly to composite airfoil trailing edge structure.
Gas turbine engines typically include a compressor section, a combustor section and a turbine section. During operation, air is pressurized in the compressor section and is mixed with fuel and burned in the combustor section to generate hot combustion gases. The hot combustion gases are communicated through the turbine section, which extracts energy from the hot combustion gases to power the compressor section and other gas turbine engine loads.
Both the compressor and turbine sections may include alternating series of rotating blades and stationary vanes that extend into the core flow path of the gas turbine engine. For example, in the turbine section, turbine blades rotate and extract energy from the hot combustion gases that are communicated along the core flow path of the gas turbine engine. The turbine vanes, which generally do not rotate, guide the airflow and prepare it for the next set of blades.
A mid turbine frame is provided between the high and low pressure turbine sections. One type of turbine frame is constructed from a composite material, which is difficult to manufacture. It is desirable to have a small trailing edge radius for aerodynamic performance but as a result, a continuous layer of plies cannot be used at the trailing edge. Instead, the plies terminate at ends that are joined at the trailing edge.
Typically, components are passed through some of the mid turbine frame airfoils. There is a significant differential pressure from the interior of the mid turbine frame to its exterior. As a result of the differential pressure across the airfoil wall, the trailing edge, in particular around the suction side, will tend to bulge open and split the trailing edge.